Biodegradable polymeric endoluminal sealing process, apparatus and polymeric products for use therein

ABSTRACT

A novel process for paving or sealing the interior surface of a tissue lumen by entering the interior of the tissue lumen and applying a polymer to the interior surface of the tissue lumen. This is accomplished using a catheter which delivers the polymer to the tissue lumen and causes it to conform to the interior surface of the lumen. The polymer can be delivered to the lumen as a monomer or prepolymer solution, or as an at least partially preformed layer on an expansile member.

RELATED APPLICATIONS

[0001] This application is a continuation of 09/624,055, filed Jul. 24,2000, which is a divisional of 09/327,715, filed Jun. 08, 1999, which isa continuation of 08/481,646, filed Jun. 7, 1995, now U.S. Pat. No.5,947,977, which is a divisional of 08/182,516, filed Jan. 14, 1994, nowU.S. Pat. No. 5,674,287, which is a FWC of 07/651,346, filed Apr. 19,1991 (abandoned), which is a national of PCT/US89/03593, filed Aug. 23,1989 which is a CIP of 07/235,998, filed Aug. 24, 1988 (abandoned);07/651,346 also is a CIP of 07/593,302, filed Oct. 3, 1990 (abandoned)which is a FWC of 07/235,998, filed Aug. 24, 1988 (abandoned).

BACKGROUND OF THE INVENTION

[0002] This invention relates to a novel method for the in vivo pavingand sealing of the interior of organs or organ components and othertissue cavities, and to apparatus and partially preformed polymericproducts for use in this method. The tissues involved may be thoseorgans or structures having hollow or tubular geometry, for exampleblood vessels such as arteries or veins, in which case the polymericproducts are deposited within the naturally occurring lumen.Alternatively, the tissue may be a normally solid organ in which acavity has been created either as a result of an intentional surgicalprocedure or an accidental trauma. In this case, the polymeric productis deposited in the lumen of the cavity.

[0003] Often times, the hollow or tubular geometry of organs hasfunctional significance such as in the facilitation of fluid or gastransport (blood, urine, lymph, oxygen or respiratory gases) or cellularcontainment (ova, sperm). Disease processes may affect these organs ortheir components by encroaching upon, obstructing or otherwise reducingthe cross-sectional area of the hollow or tubular elements.Additionally, other disease processes may violate the native boundariesof the hollow organ and thereby affect its barrier function and/orcontainment ability. The ability of the organ or structure to properlyfunction is then severely compromised. A good example of this phenomenacan been seen by reference to the coronary arteries.

[0004] Coronary arteries, or arteries of the heart, perfuse the actualcardiac muscle with arterial blood. They also provide essentialnutrients and allow for removal of metabolic wastes and for removal ofmetabolic wastes and for gas exchange. These arteries are subject torelentless service demands for continuous blood flow throughout the lifeof the patient.

[0005] Despite their critical life supporting function, coronaryarteries are often subject to attack through several disease processes,the most notable being atherosclerosis or hardening of the arteries.Throughout the life of the patient, multiple factors contribute to thedevelopment of microscopic and/or macroscopic vascular lesions known asplaques.

[0006] The development of a plaque lined vessel typically leads to anirregular inner vascular surface with a corresponding reduction ofvessel cross-sectional area. The progressive reduction incross-sectional area compromises the flow through the vessel. Forexample, the effect on the coronary arteries, is a reduction in bloodflow to the cardiac muscle. This reduction in blood flow, withcorresponding reduction in nutrient and oxygen supply, often results inclinical angina, unstable angina or myocardial infarction (heart attack)and death. The clinical consequences of the above process and itsoverall importance are seen in that atherosclerotic coronary arterydisease represents the leading cause of death in the United Statestoday.

[0007] Historically, the treatment of advanced atherosclerotic coronaryartery disease i.e. beyond that amenable to therapy via medicationalone, involved cardio-thoracic surgery in the form of coronary arterybypass grafting (CABG). The patient is placed on cardio-pulmonary bypassand the heart muscle is temporarily stopped. Repairs are then surgicallyaffected on the heart in the form of detour conduit grafted vesselsproviding blood flow around obstructions. While CABG has been perfectedto be quite effective it carries with it inherent surgical risk andrequires a several week, often painful recuperation period. In theUnited States alone approximately 150-200 thousand people are subjectedto open heart surgery annually.

[0008] In 1977 a major advance in the treatment of atheroscleroticcoronary artery disease occurred with the introduction of a techniqueknown as Percutaneous Transluminal Coronary Angioplasty (PTCA). PTCAinvolves the retrograde introduction, from an artery in the arm or leg,up to the area of vessel occlusion, of a catheter with a small dilatingballoon at its tip. The catheter is snaked through the arteries viadirect fluoroscopic guidance and passed across the luminal narrowing ofthe vessel. Once in place, the catheter balloon is inflated to severalatmospheres of pressure. This results in “cracking”, “plastic” orotherwise mechanical deformation of the lesion or vessel with asubsequent increase in the cross-sectional area. This in turn reducesobstruction, and trans-lesional pressure gradients and increases bloodflow.

[0009] PTCA is an extremely effective treatment with a relatively lowmorbidity and is rapidly becoming a primary therapy in the treatment ofatherosclerotic coronary disease throughout the United States and theworld. By way of example, since its introduction in 1977, the number ofPTCA cases now exceeds 150,000 per annum in the United States and, forthe first time in 1987, surpassed the number of bypass operationsperformed. Moreover, as a result of PTCA, emergency coronary arterybypass surgery is required in less than four percent of patients.Typically, atherosclerosis is a diffuse arterial disease processexhibiting simultaneous patchy involvement in several coronary arteries.Patients with this type of widespread coronary involvement, whilepreviously not considered candidates for angioplasty, are now beingtreated due to technical advances and increased clinical experience.

[0010] Despite the major therapeutic advance in the treatment ofcoronary artery disease which PTCA represents, its success has beenhampered by the development of vessel renarrowing or reclosure postdilation. During a period of hours or days post procedure, significanttotal vessel reclosure may develop in up to 10% of cases. This isreferred to as “abrupt reclosure”. However, the more common and majorlimitation of PTCA, is the development of progressive reversion of thevessel to its closed condition, negating any gains achieved from theprocedure.

[0011] This more gradual renarrowing process is referred to as“restenosis.” Post-PTCA follow-up studies report a 10-50% incidence(averaging approximately 30%) of restenosis in cases of initiallysuccessful angioplasty. Studies of the time course of restenosis haveshown that it is typically an early phenomenon, occurring almostexclusively within the six months following an angioplasty procedure.Beyond this six-month period, the incidence of restenosis is quite rare.Despite recent pharmacological and procedural advances, little successhas been achieved in preventing either abrupt reclosure or restenosispost-angioplasty.

[0012] Restenosis has become even more significant with the increasinguse of multi-vessel PTCA to treat complex coronary artery disease.Studies of restenosis in cases of multi-vessel PTCA reveal that aftermulti-lesion dilation, the risk of developing at least one recurrentcoronary lesion range from 26% to 54% and appears to be greater thanthat reported for single vessel PTCA. Moreover, the incidence ofrestenosis increases in parallel with the severity of thepre-angioplasty vessel narrowing. This is significant in light of thegrowing use of PTCA to treat increasingly complex multi-vessel coronaryartery disease.

[0013] The 30% overall average restenosis rate has significant costsincluding patient morbidity and risks as well as medical economic costsin terms of follow-up medical care, repeat hospitalization and recurrentcatheterization and angioplasty procedures. Most significantly, prior torecent developments, recurrent restenosis following multiple repeatangioplasty attempts could only be rectified through cardiac surgerywith the inherent risks noted above.

[0014] In 1987 a mechanical approach to human coronary artery restenosiswas introduced by Swiss investigators referred to as “IntracoronaryStenting”. An intracoronary stent is a tubular device made of fine wiremesh, typically stainless steel. The Swiss investigators utilized astent of the Wallsten design as disclosed and claimed in U.S. Pat. No.4,655,771. The device can be configured in such a manner as to be of lowcross-sectional area. In this “low profile” condition the mesh is placedin or on a catheter similar to those used for PTCA. The stent is thenpositioned at the site of the vascular region to be treated. Once inposition, the wire mesh stent is released and allowed to expand to itsdesired cross-sectional area generally corresponding to the internaldiameter of the vessel. Similar solid stents are also disclosed in U.S.Pat. No. 3,868,956 to Alfidi et al.

[0015] The metal stent functions as a permanent intravascular scaffold.By virtue of its material properties, the metal stent providesstructural stability and direct mechanical support to the vascular wall.Stents of the Wallsten design are self-expanding due to their helical“spring” geometry. Recently, U.S. investigators introduced slotted steeltubes and extended spring designs. These are deployed though applicationof direct radial mechanical pressure conveyed by a balloon at thecatheter tip. Such a device and procedure are claimed in U.S. Pat. No.4,733,665 to Palmaz. Despite the significant limitations and potentiallyserious complications discussed below, this type of stenting has beensuccessful with an almost 100% acute patency rate and a marked reductionin the restenosis rate.

[0016] The complications associated with permanent implants such as thePalmaz device result from both the choice of material, i.e., metal orstainless steel, as well as the inherent design deficiencies in thestenting devices. The major limitation lies in the permanent placementof a non-retrievable, non-degradable, foreign body in a vessel to combatrestenosis which is predominantly limited to the six-month time periodpost-angioplasty. There are inherent, significant risks common to allpermanent implant devices. Moreover, recent studies have revealed thatatrophy of the media, the middle arterial layer of a vessel, may occuras a specific complication associated with metal stenting due to thecontinuous lateral expansile forces exerted after implantation.

[0017] These problems are even more acute in the placement of apermanent metallic foreign body in the vascular tree associated with thecardiac muscle. Coronary arteries are subjected to the most extremeservice demands requiring continuous unobstructed patency with unimpededflow throughout the life of the patient. Failure in this system willlead to myocardial infarction (heart attack) and death. In addition, thetorsional and other multi-directional stresses encountered in the heartdue to its continuous oscillatory/cyclic motion further amplifies therisks associated with a permanent, stiff metallic intra-arterial implantin the coronary bed.

[0018] It has been observed that, on occasion, recurrent intravascularnarrowing has occurred post-stent placement in vessels during a periodof several weeks to months. Typically, this occurs “peri-stent”, i.e.,immediately up or down stream from the stent. It has been suggested thatthis may relate to the significantly different compliances of the vesseland the stent, sometimes referred to as “compliance mismatch”. Asidefrom changes in compliance another important mechanism leading toluminal narrowing above and below the stent may be the changes in shearforces and fluid flows encountered across the sharp transitions of thestent-vessel interface. Further supporting evidence has resulted fromstudies of vascular grafts which reveal a higher incidence of thrombosisand eventual luminal closure also associated with significant compliancemismatch.

[0019] To date known stent designs, i.e. tubular, wire helical orspring, scaffold design have largely been designed empirically withoutconsideration or measurement of their radial stiffness. Recent studiesmeasuring the relative radial compressive stiffness of known wirestents, as compared to physiologically pressurized arteries, have foundthem to be much stiffer than the actual biological tissue. These studieslend support to the concept of poor mechanical biocompatibility ofcurrent available stents.

[0020] Conventional metal stenting is severely limited since it isdevice dependent and necessitates a myriad of individual stents as wellas multiple deployment catheters of varying lengths and sizes toaccommodate individual applications. Additionally, metal stents providea relatively rigid nonflexible structural support which is not amenableto a wide variety of endoluminal geometries, complex surfaces, luminalbends, curves or bifurcations.

[0021] These identified risks and limitations of metal stents haveseverely limited their utility in coronary artery applications. As of1988, a partial self-imposed moratorium exists in the use of helicalmetal stents to treat human coronary artery diseases. Presented in theUnited States, a spring-like wire coil stent has been approved only forshort term use as an emergency device for patients with irreparablyclosed coronary arteries following failed PTCA while in transit toemergency bypass surgery. An alternative to the use of stents has nowbeen found which has broad applications beyond use in coronary arteryapplications for keeping hollow organs open and in good health.

SUMMARY OF THE INVENTION

[0022] The present invention provides a solution to the problem ofrestenosis following angioplasty, without introducing the problemsassociated with metal stents. Specifically, the invention provides anovel method for endoluminal paving and sealing (PEPS) which involvesapplication of a polymeric material to the interior surface of the bloodvessel. In accordance with this method, a polymeric material, either inthe form of a monomer or prepolymer solution or as an at least partiallypre-formed polymeric product, is introduced into the lumen of the bloodvessel and positioned at the point of the original stenosis. Thepolymeric product is then reconfigured to conform to and maintainintimate contact with the interior surface of the blood vessel such thata paving and sealing coating is achieved.

[0023] The PEPS approach is not limited to us in connection withrestenosis, however, and can also be effectively employed in any holloworgan to provide local structural support, a smooth surface, improvedflow and sealing of lesions. In addition, the polymeric paving andsealing material may incorporate therapeutic agents such as drugs, drugproducing cells, cell regeneration factors or even progenitor cells ofthe same type as the involved organ or histologically different toaccelerate healing processes. Such materials with incorporatedtherapeutic agents may be effectively used to coat or plug surgically ortraumatically formed lumens in normally solid organs as well as thenative or disease generated lumens of hollow or tubular organs.

[0024] For use in these applications, the present invention provides atleast partially preformed polymeric products. These products may haveany of a variety of physical shapes and sizes in accordance with theparticular application. The invention also provides apparatusspecifically adapted for the positioning of the polymeric material,these including partially pre-formed polymeric products, at the interiorsurface of an organ for the subsequent chemical or physicalreconfiguration of the polymeric material such that it assumes a desiredmolded or customized final configuration.

BRIEF DESCRIPTION OF THE DRAWING

[0025]FIG. 1 shows an amorphous geometry of the PEPS polymer coatingbefore and after deployment;

[0026]FIG. 2 shows a stellate geometry of the PEPS polymer coatingbefore and after deployment;

[0027]FIG. 3 shows a linear feathered polymer strip applied to “one”wall before and after deployment;

[0028]FIG. 4 shows a large patch of sprayed on polymer material beforeand after deployment;

[0029]FIG. 5 shows a porous tubular form geometry before and afterdeployment;

[0030]FIG. 6 shows a spot geometry of the PEPS process before and afterdeployment;

[0031]FIG. 7 shows a spiral form application of the PEPS process beforeand after deployment;

[0032]FIG. 8 shows an arcuate (radial, arc) patch geometry of the PEPSpolymer before and after deployment;

[0033]FIG. 9 shows a process for using PEPS to treat an artificiallycreated tissue lumen;

[0034]FIG. 10 shows two lumen catheters according to the invention;

[0035]FIG. 11 shows surface contours of expansile members useful incatheters according to the invention;

[0036]FIG. 12 shows three catheters according to the invention;

[0037]FIG. 13 shows four lumen catheters according to the invention;

[0038]FIG. 14 shows five lumen catheters according to the invention;

[0039]FIG. 15 shows six lumen catheters according to the invention;

[0040]FIG. 16 shows seven lumen catheters according to the invention;

[0041]FIG. 17 shows a distal occlusion catheter and a polymer deliverycatheter in a vessel;

[0042]FIG. 18 shows in cross-section a polymeric sleeve before insertionin a blood vessel; the sleeve after insertion in the vessel and afterexpansion;

[0043]FIG. 19 is a cross-sectional comparison of an initial polymericsleeve and an expanded polymeric sleeve;

[0044]FIG. 20 shows enmeshed discontinuous polymeric material arrayed ona catheter with a retractable sheath; and

[0045]FIG. 21 shows variations in apertures for polymer delivery to atissue lumen.

DETAILED DESCRIPTION OF THE INVENTION

[0046] In general, PEPS involves the introduction of a polymericmaterial into a selected location within a lumen in tissue, i.e., anorgan, an organ component or cavernous component of an organism, and thesubsequent reconfiguration of the polymeric material to form a sealingin intimate and conforming contact with or paving the interior surface.As used herein, the term “sealing” or “seal” means a coating ofsufficiently low porosity that the coating serves a barrier function.The term “paving” refers to coatings which are porous or perforated. Byappropriate selection of the polymeric material employed and of theconfiguration of the coating or paving, PEPS provides a uniquecustomizable process, which can be utilized as a given biological orclinical situation dictates.

[0047] The basic requirements for the polymeric material to be used inthe PEPS process are biocompatibility and the capacity to be chemicallyor physically reconfigured under conditions which can be achieved invivo. Such reconfiguration conditions may involve heating, cooling,mechanical deformation, e.g., stretching, or chemical reactions such aspolymerization or crosslinking.

[0048] Suitable polymeric materials for use in the invention includepolymers and copolymers of carboxylic acids such as glycolic acid andlactic acid, polyurethanes, polyesters such as poly(ethyleneterephthalate), polyamides such as nylon, polyacrylonitriles,polyphosphazines, polylactones such as polycaprolactone, andpolyanhydrides such as poly[bis(p-carboxphenoxy)propane anhydride] andother polymers or copolymers such as polyethylene, polyvinyl chlorideand ethylene vinyl acetate.

[0049] Other bioabsorbable polymers could also be used either singly orin combination, or such as homopolymers and copolymers ofdelta-valerolactone, and p-dioxanone as well as their copolymers withcaprolactone. Further, such polymers can be cross-linked withbiscaprolactone.

[0050] Preferably PEPS utilizes biodegradable polymers, with specificdegradation characteristics to provide sufficient lifespan for theparticular application. As noted above, a six month lifespan is probablysufficient for use in preventing restenosis; shorter or longer periodsmay be appropriate for other therapeutic applications.

[0051] Polycaprolactone as disclosed and claimed in U.S. Pat. No.4,702,917 to Schnidler, incorporated herein by reference, is a highlysuitable bioabsorbable polymer for use in the PEPS process, particularlyfor prevention of restenosis. Polycaprolactone possesses adequatemechanical strength being mostly crystalline even under quenchingconditions. Despite its structural stability, polycarpolactone is muchless rigid than the metals used in traditional stenting. This minimizesthe risk of acute vessel wall damage from sharp or rough edges.Furthermore, once polycaprolactone has been deployed its crystallinestructure will maintain a constant outside diameter. This eliminates therisk often associated with known helical or spring metal stents whichafter being expanded in vivo have a tendency to further expand exertingincreasing pressure on the vessel wall.

[0052] The rate of bioabsorption of polycaprolactone is ideal for thisapplication. The degradation process of this polymer has been wellcharacterized with the primary degradation product being nonparticulate,nontoxic, 6-hydroxy hexanoic acid of low acidity. The time ofbiodegradation of polycaprolactone can be adjusted through the additionof various copolymers.

[0053] Polycaprolactone is a preferred polymer for use in the PEPSprocess because it has attained favorable clinical acceptability and isin the advanced stages of FDA approval. Polycaprolactone has acrystalline melting point of 60° C. and can be deployed in vivo via amyriad of techniques which facilitate transient heating and varyingdegrees of mechanical deformation or application as dictated byindividual situations. This differs markedly from other bioabsorbablepolymers such as polyglycolide and polylactide which melt at much highertemperatures of 180° C. and pose increased technical constraints as faras the delivery system affording polymer sculpting without deleterioustissue exposure to excessive temperatures or mechanical forces.

[0054] Polyanhydrides have been described for use as drug carriermatrices by Leong et al., J. Biomed. Mat. Res. 19, 941-955 (1985). Thesematerials frequently have fairly low glass transition temperatures, insome cases near normal body temperature, which makes them mechanicallydeformable with only a minimum of localized heating. Furthermore, theyoffer erosion times varying from several months to several yearsdepending on particular polymer selected.

[0055] The polymeric materials may be applied in custom designs, withvarying thicknesses, lengths, and three-dimensional geometries (e.g.,spot, stellate, linear, cylindrical, arcuate, spiral) to achieve varyingfinished geometries as depicted in FIGS. 1-8. Further, PEPS may be usedto apply polymer to the inner surfaces of hollow, cavernous, or tubularbiological structures (whether natural or artificially formed) in eithersingle or multiple polymer layer configurations. PEPS may also be used,where appropriate, to occlude a tissue lumen completely.

[0056] The polymeric material used in PEPS can be combined with avariety of therapeutic agents for onsite delivery. Examples for use incoronary artery applications are anti-thrombotic agents, e.g.,prostacyclin and salicylates, thrombolytic agents e.g. streptokinase,urokinase, tissue plasminogen activator (TPA) and anisoylatedplasminogen-streptokinase activator complex (APSAC), vasodilating agentsi.e. nitrates, calcium channel blocking drugs, anti-proliferative agentsi.e. colchicine and alkylating agents, intercalating agents, growthmodulating factors such as interleukins, transformation growth factor βand congeners of platelet derived growth factor, monoclonal antibodiesdirected against growth factors, anti-inflammatory agents, bothsteroidal and non-steroidal, and other agents which may modulate vesseltone, function, arteriosclerosis, and the healing response to vessel ororgan injury post intervention. In applications where multiple polymerlayers are used different pharmacological agents could be used indifferent polymer layers. Moreover, PEPS may be used to effectpharmaceutical delivery focally within the vessel wall, i.e. media.

[0057] The polymeric material in accordance with the invention may alsohave incorporated in it living cells to serve any of several purposes.For examples, the cells may be selected, or indeed designed usingprinciples of recumbent DNA technology, to produce specific agents suchas growth factors. In such a way, a continuously regenerating supply ofa therapeutic agent may be provided without concerns for stability,initial overdosing and the like.

[0058] Cells incorporated in the polymeric material may also beprogenitor cells corresponding to the type of tissue in the lumentreated or other cells providing therapeutic advantage. For example,liver cells might be implanted in the polymeric material within a lumencreated in the liver of a patient to facilitate regeneration and closureof that lumen. This might be an appropriate therapy in the case wherescar tissue or other diseased, e.g. cirrhosis, fibrosis, cystic diseaseor malignancy, non-functional tissue segment has formed in the liver orother organ and must be removed. The process of carrying out suchtreatment, shown schematically in FIG. 9, involves first inserting acatheter 91 into a lumen 92 within a diseased organ segment 93. Thelumen 92 can be a native vessel, or it can be a man-made lumen, forexample a cavity produced by a laser. The catheter 91 is used tointroduce a polymeric plug 94 into the lumen 92. The catheter is thenremoved, leaving the plug 94 in place to act as a focus for new growthstemming from cells implanted along with the polymeric plug 94. If thedesire is for a more tubular structure, the plug 94 can be appropriatelyreconfigured.

[0059] Optional additions to the polymeric material such as barium,iodine or tantalum salts for X-ray radio-opacity allow visualization andmonitoring of the coating.

[0060] The technique of PEPS preferably involves the percutaneousapplication of a polymeric material, preferably a biodegradable polymersuch as polycaprolactone, either alone or mixed with other biodegradablepolymeric materials, which may optionally contain various pharmaceuticalagents for controlled sustained release of the pharmaceutical or forselective soluble factor adsorption and trapping. The polymeric materialis typically applied to the inside of an organ surface employingcombined thermal and mechanical means to manipulate the polymericmaterial. Although capable of being used during surgery, PEPS willgenerally be applied without the need for a surgical procedure usingsome type of catheter, for example novel modifications of the knowncatheter technology described above for (PTCA). PEPS is preferablyapplied using a single catheter with multiple balloons and lumens. Thecatheter should be of relatively low cross-sectional area. Typically along thin tubular catheter manipulated using fluoroscopic guidance canaccess deep into the interior of organ or vascular areas.

[0061] The polymer may be deployed in the interior of the vessel ororgan from the surface or tip of the catheter. Alternatively, thepolymer could be positioned on a balloon such as that of a standardangioplasty balloon catheter. Additionally, the polymer could be appliedby spraying, extruding or otherwise internally delivering the polymervia a long flexible tubular device consisting of as many lumens as aparticular application may dictate.

[0062] The simplest PEPS coating is a continuous coating over adesignated portion of a tissue lumen. Such a coating can be applied witha simple two lumen catheter such as those shown in FIG. 10. Lookingfirst to FIG. 10a, a suitable catheter is formed from a tubular body 100having a proximal end 101 and a distal end 102. The interior of thetubular body 100 is divided into two conduits 103 and 104 which extendfrom the proximal end 101 to apertures 105 and 106 in the tubular body.(FIGS. 10b and 10 c) Conduits 103 and 104 thus connect apertures 105 and106 with the proximal end 101 of the tubular body 100 to allow fluidflow therebetween. The proximal ends of conduits 103 and 104 arepreferably equipped with connectors 108 which allow connection withfluid supplies. Pressure connectors such as Luer® locks are suitable.

[0063] The catheter may also include markers 109 in one or morelocations to aid in locating the catheter. These markers can be, forexample, fluoroscopic radio-opaque bands affixed to the tubular body 100by heat sealing.

[0064] The catheter shown in FIGS. 10b and 10 c has an expansile memberin the form of an inflatable balloon 107 disposed over the distalaperture 105. In use, an at least a partially preformed polymeric layeror partial layer is positioned over the balloon 107 and the catheter isinserted into an appropriate position in the tissue lumen. Fluid flowthrough conduit 103 will cause the balloon 107 to inflate, stretch anddeform the polymer layer until it comes into contact with the walls ofthe tissue lumen. The other aperture 105 and conduit 103 are used tocontrol the reconfiguration of the polymeric sleeve, for example bysupplying a flow of heated liquid to soften the sleeve and render itmore readily stretchable or to stimulate polymerization of a partiallypolymerized sleeve.

[0065] Variations on this basic two lumen catheter can be made, examplesof which are shown in FIGS. 10d and 10 e. For example, FIG. 10d has ashapeable wire affixed to the tip of the catheter to aid in insertionand a traumatic and directed passage through the organism, i.e. to actas a guide wire. In FIG. 10e, the expansile member is incorporated aspart of the tubular body as a continuous element, preferably a unitaryelement. In this case, the distal tip 107 a of the catheter expands inresponse to fluid flow in conduit 103. Conduit 104 can be formed bybonding in or on the extruded catheter body a piece of the same ordifferent material in a tubular form. This type of design can also beused in more complicated multi-lumen catheters discussed below.

[0066] The polymeric material may take the form of a sleeve designed tobe readily insertable along with the catheter into the tissue lumen, andthen to be deployed onto the wall of the lumen to form the coating. Thisdeployment can be accomplished by inflating a balloon, such as balloon107 using fluid flow through conduit 103. Inflation of balloon 107stretches the polymeric sleeve causing it to press against the walls ofthe tissue lumen and acquire a shape corresponding to the lumen wall.This shape is then fixed, and the catheter removed leaving behind apolymeric paving or seal on the lumen wall.

[0067] The process of fixing the shape of the polymeric material can beaccomplished in several ways, depending on the character of the originalpolymeric material. For example, a partially polymerized material can beexpanded using the balloon after which the conditions are adjusted suchthat polymerization can be completed, e.g., by increasing the localtemperature or providing UV radiation through an optical fiber. Atemperature increase might also be used to soften a fully polymerizedsleeve to allow expansion and facile reconfiguration and local molding,after which it would “freeze” in the expanded position when the heatsource is removed. Of course, if the polymeric sleeve is a plasticmaterial which will permanently deform upon stretching (e.g.,polyethylene, polyethylene terephthalate, nylon or polyvinyl chloride),no special fixation procedure is required.

[0068] As depicted in FIG. 10b, local heating can be provided by a flowof heated liquid directly into the tissue lumen. Thermal control canalso be provided, however, using a fluid flow through or into theexpansile member or using a “leaky” partially perforated balloon suchthat temperature control fluid passes through the expansile member, orusing electrical resistive heating using a wire running along the lengthof the catheter body in contact with resistive heating elements. Thistype of heating element can make use of DC or radiofrequency (RF)current or external RF or microwave radiation. Other methods ofachieving temperature control can also be used, including laser heatingusing an internal optical fiber (naked or lensed) or thermonuclearelements.

[0069] In addition to the smooth shape shown in FIG. 10, the balloonused to configure the polymer can have other surface shapes forformation of the coatings to provide specific polymeric deploymentpatterns. For example, the balloon may be a globular shape intended fordeployment from the tip of a catheter device. (FIG. 11a) Such anarrangement would be preferred when the paving operation is beingcarried out in a cavity as opposed to a tubular organ. The balloon mightalso be thickened at the ends (FIG. 11c) or substantially helical (FIG.11d) providing a variation in coating thickness along the length of thepaved or sealed area. Such a configuration might prove advantageous inthe case where additional structural support is desired and to provide atapered edge to minimize flow disruption. Variations in coatingthickness which provide ribs running the length of the tissue lumenmight be achieved using a stellate balloon (FIG. 11e). This type ofpolymer coating would be useful in the case where additional structuralsupport is desirous combined with more continuous flow properties. Inaddition balloon shape may facilitate insertion in some cases.

[0070] Variations in the ultimate configuration of the PEPS coating canalso be achieved by using more complex deployments of the polymer on theexpansile number. For example, the polymer can be in the form of aperforated tubular sleeve, a helical sleeve or in the form ofdiscontinuous members of various shapes. These may be affixed to theexpansile member directly, for example with an adhesive or by suctionthrough perforations and the like, or to an overcoating such asdissolvable gauze-like or paper sheath (i.e., spun saccharide) or heldin place by a retractable porous sheath which will be removed with thecatheter after application.

[0071] For example, FIG. 20(a) shows an array of polymer dots. Thesedots are enmeshed in a dissolvable mesh substrate FIG. 20(b) which inturn is wrapped around the expansile member 107 of a catheter accordingto the invention (FIG. 20c). An exemplary two lumen catheter is shown inFIG. 20d (numbered as in FIG. 10b) where a retractable sheath 205surrounds the polymer dots 206 for insertion. When the catheter reachesthe application site, the sheath 205 is retracted (FIG. 20e) and theballoon 107 expanded.

[0072] It will be recognized, that the catheter depicted in FIG. 10represents a minimalistic approach to PEPS catheter design, and thatadditional lumens may be included within the catheter body to provideconduits for inflation of positioning balloons, optical fibers,additional polymer molding balloons, temperature control means, andpassage of steering or guide wires or other diagnostic devices, e.g.ultrasound catheter, or therapeutic devices such as atherectomy catheteror other lesion modifying device. For example, three lumen catheters(FIG. 12), four lumen catheters (FIG. 13), five lumen catheters (FIG.14), six lumen catheters (FIG. 15) and seven lumen catheters (FIG. 16)might be employed. A retractable sheath may also be provided whichextends over the polymer during insertion to prevent prematureseparation of the polymer from the catheter. In addition, catheters mayhave telescoping sections such that the distance between the occludingballoons can be varied.

[0073] Looking for example at the six lumen catheters in FIG. 15b, twopositioning balloons 150 and 151, both connected to conduit 152.Positioning balloons 150 and 151 serve to fix the position of thetubular body 100 within a tissue lumen and isolate the portion of thetissue lumen between them where the PEPS coating will be applied.Expansile member 153 is provided with circulating flow via conduits 154and 155. This can be used to provide temperature control to the isolatedportion of the tissue lumen, as well as acting to configure thepolymeric coating formed by expanding a polymeric sleeve and otherdeployed form fitted over expansile member 153. In the catheter shown inFIG. 15b, a temperature control solution or a therapeutic solution isadvantageous provided through conduit 156, with conduit 157 acting as adrain line (or vice versa) to allow flow of fluid through the isolatedportion of the tissue lumen (“superfusion”). Such a drain line is notrequired, however, and a simple infusion catheter could omit one of theconduits 156 or 157 as in the five lumen designs of FIG. 14. The sixthconduit 158 is also optional, but can be advantageously used for guidewires, diagnostic or therapeutic device passage, or distal fluidperfusion. If conduit 158 has an aperture proximal to balloon 151, itcan be used as a by-pass conduit for passive perfusion during occlusion.

[0074] The incorporation in the catheter of positioning balloons whichocclude a section of the tissue lumen makes it possible to utilizesolutions of monomers or prepolymers and form the coating in situ.Looking for example at four lumen catheters shown in FIG. 13b, anisolation zone is created by inflating balloons 131 and 132 so that theypress against the tissue lumen. While expansile member 133 could be usedto deform a polymeric sleeve or other deployment form, it can also beused to define the size and environmental conditions (e.g. temperature)of the lumen region.

[0075] Application of the polymeric material may be accomplished byextruding a solution of monomers or prepolymers through the aperture 134to coat or fill the tissue lumen. The formation of a polymer coating canbe controlled by introducing crosslinking agents or polymerizationcatalysts together with the monomer or prepolymer solution and thenaltering the conditions such that polymerization occurs. Thus, a flow ofheated fluid into expansile member 133 can increase the localtemperature to a level sufficient to induce or acceleratepolymerization. Alternatively, the monomer/prepolymer solution might beintroduced cold, with metabolic temperature being sufficient to inducepolymerization. The other lumen 135 acts as a drain line in superfusionapplications.

[0076] The polymeric material can be introduced to the tissue lumenthrough a simple aperture in the side of the tube as shown in FIG. 21a,or through a raised aperture (FIG. 21b). A shaped nozzle which isextendable away from the surface of the tubular body (FIG. 21e) can alsobe used. The material can be extruded through, or it can be subjected toflow restriction to yield a spray application. This flow restriction canbe adjustable to control the spray. In addition, localized accelerationat the tip of the nozzle can be used, for example, via a piezoelectricelement to provide sprayed application.

[0077] The catheters bodies for use in this invention can be made of anyknown material, including metals, e.g. steel, and thermoplasticpolymers. Occluding balloons may be made from compliant materials suchas latex or silicone, or non-compliant materials such aspolyethyleneterephthalate (PET). The expansile member is preferably madefrom non-compliant materials such as PET, PVC, polyethylene or nylon.The expansile number may optionally be coated with materials such assilicones, polytetra-fluoreothylene (PTFE), hydrophilic materials likehydrated hydrogels and other lubricious materials to aid in separationof the polymer coating.

[0078] In addition to arteries, i.e., coronary, femeroiliac, carotid andvertebro-basilar, the PEPS process may be utilized for otherapplications such as paving the interior of the veins, ureters,urethrae, bronchi, bilary and pancreatic duct systems, the gut, eye andspermatic and fallopian tubes. The sealing and paving of the PEPSprocess can also be used in other direct clinical applications even atthe coronary level. These include but are not limited to the treatmentof abrupt vessel reclosure post PCTA, the “patching” of significantvessel dissection, the sealing of vessel wall “flaps”, i.e. secondary tocatheter injury or spontaneously occuring, the sealing of aneurysmalcoronary dilations associated with various arteritidies. Further, PEPSprovides intraoperative uses such as sealing of vessel anostomosesduring coronary artery bypass grafting and the provision of a bandagedsmooth polymer surface post endarterectomy.

[0079] The unique pharmaceutical delivery function of the PEPS processmay be readily combined with “customizable” deployment geometrycapabilities to accommodate the interior of a myriad of complex organ orvessel surfaces. Most importantly, this customized geometry can be madefrom structurally stable yet biodegradable polymers. The ability totailor the external shape of the deployed polymer through melted polymerflow into uneven surface interstices, while maintaining a smoothinterior surface with good flow characteristics, will facilitate betterstructural support for a variety of applications including eccentriccoronary lesions which by virtue of their geometry are not well bridgedwith conventional metal stents.

[0080] As noted above, the polymer substrate used in PEPS may befashioned, for example, out of extruded tubes of polycaprolactone and/orcopolymers. The initial predeployment design and size of the polymersleeve will be dictated by the specific application based upon the finaldeployed physical, physiological and pharmacological properties desired.

[0081] For coronary artery application, predeployment tubes of about 10to 20 mm in length and about 1 to 2 mm in diameter would be useful. Theinitial wall thickness of the resulting in vivo polymer layer may bevaried depending upon the nature of the particular application. Ingeneral coating procedures require polymer layers of about 0.005 mm to0.50 mm while layers which are designed to give structural support canvary from 0.05 mm to 5.0 mm.

[0082] The polymer tube walls may be processed prior to insertion witheither laser or chemical etching, pitting, slitting or perforationdepending upon the application. In addition, the shape of any micro (10nm to 1 μm) or macro (>1 μm up to about 15 μm) perforation may befurther geometrically modified to provide various surface areas on theinner versus outer seal surface. The surfaces of the predeployed polymermay be further modified with bound, coated, or otherwise applied agents,i.e., cyanoacrylates or biological adhesives such as those derived fromfungal spores, the sea mussel or autologous fibrinogen adhesive derivedfrom blood.

[0083] For PEPS applications involving the coronary arteries, thepolymer tubes (if in an initial tubular configuration), shouldpreferably have perforations or pores, of a size dictated by theparticular application. This will ensure a symmetric expansion of theencasing polymeric sealant. By using a fragmented tubular polymersurface with corresponding expansions along predicted perforations(i.e., the slots) a significant mechanical stability is provided. Inaddition, this minimizes the amount of foreign material placed withinthe vessel.

[0084] Depending on the polymer and pharmaceutical combination and theconfiguration, PEPS may be used to coat or bandage the organ innersurface with a thin adhesive partitioning polymer film or layer of about0.005 mm to 0.50 mm. Biodegradable polymers thus applied to an internalorgan or vessel surface will act as an adherent film “bandage”. Thisimproved surface, with desirable rheologic and adherence properties,facilitates improved fluid or gas transport in and through the body orlumen of the vessel or hollow organ structure and acts to reinstateviolated native surfaces and boundaries.

[0085] The ultimate in vivo deployed geometry of the polymer dictatesthe final function of the polymer coating. The thinner applicationsallow the polymer film to function as a coating, sealant and/orpartitioning barrier, bandage, and drug depot. Complex internalapplications of thicker layers of polymer, such as intra-vessel orintra-luminal applications, may actually provide increased structuralsupport and depending on the amount of polymer used in the layer mayactually serve in a mechanical role to maintain vessel or organ potency.

[0086] For example, lesions which are comprised mostly of fibromuscularcomponents have a high degree of visco-elastic recoil. These lesionswould require using the PEP process to apply an intraluminal coating ofgreater thickness and extent so as to impart more structural stabilitythereby resisting vessel radial compressive forces. The PEPS process inthis way provides structural stability and is generally applicable forthe maintenance of the intraluminary geometry of all tubular biologicalorgans or substructure. It may be used in this way following thetherapeutic return of normal architecture associated with either balloondilation (PTCA), atherectomy, lesion spark, thermal or other mechanicalerosion, “G-lazing”, welding or laser recanalization.

[0087] An important feature of the PEPS technique is the ability tocustomize the application of the polymer to the internal surface of avessel or organ as dictated by the particular application. This resultsin a variety of possible geometries or polymer as well as a variety offorms. These multi-geometry, multi-form polymer structures may beadjusted to correspond to particular functions. (FIGS. 1-8)

[0088] With particular reference to FIGS. 1-8 the PEPS process may beaffectuated so that the focal application of polymer to the vessel ororgan results in either an amorphous geometry, FIG. 1, stellategeometry, FIG. 2, or spot geometry, FIG. 6. Additional geometries couldinclude a linear feathered polymer strip applied to a particular area ofthe vessel wall as shown in FIG. 3. FIG. 4 shows a large patch ofpolymer which can be sprayed on using a variety of known techniques.Another form of PEPS application to be utilized in instances, e.g.,where structural stability need be imparted to the vessel would be theporous tubular form shown in FIG. 5. Other types of PEPS applicationswhich would impart structural stability to the vessel would be thespiral form application shown in FIG. 7, or the arcuate (radial, arc)patch as shown in FIG. 8.

[0089] Conversely, in cases where the severely denuded lesions haveirregular surfaces with less firbromuscular components, the PEPS processcan be used to provide only a thin polymer film to act as a bandage.

[0090] The PEPS' process is significantly different and is conceptuallyan advance beyond stents and stenting in achieving vessel patency.Stents have been designed with the underlying primary function ofproviding a relatively stiff structural support resist post PTCA, vesselreclosure caused by the vessel's spring-like characteristics. It hasbeen increasingly demonstrated that cellular and biochemical mechanismsas opposed to physical “spring-like” coils, are of a much greatersignificance in preventing vessel reclosure and PEPS addresses thesemechanisms.

[0091] The specific object and features of the PEPS process are bestunderstood by way of illustration with reference to the followingexamples and figures.

EXAMPLE 1

[0092] The invention may be readily understood through a description ofan experiment performed in vitro using a mock blood vessel made fromtransparent plastic tubing using a heat-balloon type deployment catheterreference to FIG. 17.

[0093] The balloon delivery catheter 170 is first positioned in thevessel 171 at the area of the occlusion. Before insertion, apolycaprolactone polymer sleeve 172 containing additives, e.g. to aidX-ray radio opacity, for drug delivery or to promote surface adhesion,is placed in a low profile condition surrounding a balloon at the distalend of the delivery catheter 170. The delivery catheter with thepolycaprolactone tube is then inserted balloon end first into the vessel171 and manipulated into position, i.e., the area of the vessel to betreated.

[0094] A separate occlusion catheter 173 is employed to restrict “blood”flow through the vessel. The distal end of the occlusion catheter 173 isinflated to create a stagnant column of “blood” in the vessel around theballoon delivery catheter and polycaprolactone tube. Saline solution atabout 60-80° is injected through a lumen in the occlusion catheter 173or the delivery catheter 170 in the case of using a catheter accordingto the invention into the area surrounding the delivery catheter,balloon and polycaprolactone tube. Once the polycaprolactone tubebecomes pliable, the delivery catheter balloon is inflated to push thepolycaprolactone sleeve out against the interior wall thereby locallysealing and/or paving the vessel.

[0095] The polycaprolactone expands and/or flows, conforming to theinner surface of the vessel, flowing into and filling in surfaceirregularities thereby creating a “tailored” fit. Further, the deployedinterior surface of the PEPS polymer is smooth providing an increasedvessel (lumen) cross-section diameter and a rheologically advantageoussurface with improved blood flow. Upon removal of heated saline solutionthe polymer recrystallizes to provide a paved surface of the vessel wallinterior.

[0096] The deployment catheter balloon is then deflated leaving thepolycaprolactone layer in place. The balloon section of the occlusioncatheter is deflated and, blood flow was allowed to return to normal andthe deployment catheter was removed leaving the recrystalizedpolycaprolactone layer in place within the vessel.

[0097] Over the course of time the polycaprolactone seal will becomecovered with proteinaceous biological thin film coat. Depending upon theexact seal chemical composition, the polymer will then biodegrade, at apredetermined rate and “dissolve” into the bloodstream or be absorbedinto the vessel wall. While in intimate contact with the vessel wall,pharmacological agents if embedded or absorbed in the polycaprolactonewill have a “downstream” effect if released slowly into the bloodstreamor may have a local effect on the blood vessel wall, therebyfacilitating healing of the angioplasty site, controlling or reducingexuberant medial smooth muscle cell proliferation, promoting effectivelesion endothelialyation and reducing lesion thromogenicity.

EXAMPLE 2

[0098] Polycaprolactone in an initial macroporous tubular configurationwas placed in a low profile form in bovine coronary arteries and caninecarotid arteries. In the process of deployment the vessels werepurposely overextended and sealed through thermal and mechanicaldeformation of the polymer. FIG. 18 shows a cross-section of the polymertube 180 before insertion in the bovine artery, after insertion in theartery in the artery 181, and after expansion 182. The initial polymertube 180, is smaller in diameter than the artery 181. After deployment,the thin film of polymer 182 can be seen coating the inner surface ofthe sealed vessel with the vessel remaining erect. The vessel remaineddilated to about 1.5 times the original diameter because of the abilityof the polymer to keep it fixed. FIG. 19 shows a cross-section of thepolymer before insertion 190 and removed after insertion andreconfiguration 191 in a canine artery. This figure clearly shows thestretching and thinning of the polymer wall.

[0099] All polymer sealed vessels remained dilated with a thin layer ofmacroporous polymer providing a new barrier surface between the vessellumen and the vessel wall constituents. The unsealed portion of thevessels did not remain dilated.

[0100] These examples demonstrate that the PEPS process may if desiredprovide polymer application with a relatively large degree of surfacearea coverage and an effective polymer barrier shield. As such, thepolymer barrier-shield may, if desired, impart sufficient structuralstability to maintain a selected vessel diameter. The selected finalvessel diameter at which a vessel is sealed is dictated by theparticular physiological variables and therapeutic goals which confrontthe PEPS user.

[0101] The geometry of the pre and post PEPS application sites may bereadily varied. PEPS may be used to merely coat an existing vessel ororgan geometry. Alternatively, the PEPS process may be used to impartstructural stability to a vessel or organ the geometry of which wasaltered prior to the PEPS application. In addition, the PEPS process mayitself alter the geometry of the vessel or organ by shaping thegeometry. With reference to FIG. 18 this latter process was used toexpand the vessel 181.

[0102] A specific and important attribute of the PEPS technique and thepolymers which are employed is the significantly lower degree ofcompliance mismatch or similarities of stiffness (inverse of compliance)between the vessel and the polymer seal as compared to metal stents. Thevessel damage from compliance mismatch discussed above may be eliminatedby the PEPS process utilizing a variety of available polymers.Additionally, compliance mismatch greatly modifies the characteristicsof fluid wave transmission along the vessel with resultant change inlocal flow properties, development of regional change in shear forcesand a subsequent vessel wall hypertrophy which acts to reduce vesselcross-sectional area and reduces blood flow. Further, the substructuralelimination of compliance mismatch of the PEPS technique at firstminimizes and then, upon dissolution eliminates local flow abnormalitiesand up and downstream transition zone hypertrophy associated with metalstenting.

[0103] PEPS has the flexibility of being safely and effectively usedpropyhlactically at the time of initial PTCA in selected patients orbeing incorporated as part of the original dilation procedure as asecond stage prophylactic vessel surface “finishing” process. Forexample, the invasive cardiologist may apply the PEPS technique on awide clinical basis after the first episodes of restenosis. In addition,because the PEPS technique significantly aids in the vascular healingprocess post intervention, it may be readily used prophylactically afterinitial angioplasty prior to any incidence of restenosis. This wouldfree the patient from the risks of repeat intracoronary procedure aswell as those associated with metal stenting.

1. A catheter device for application of a polymeric coating to a tissue lumen comprising a flexible tubular body having proximal and distal ends, which tubular body defines a lumen divided into a plurality of sublumens, each sublumen extending from the proximal end of the tubular body toward the distal end of the tubular body and connecting to at least one aperture in the tubular body whereby each sublumen forms a conduit for fluid flow between at least one aperture in the tubular body and the proximal end of the tubular body, characterized in that at least one of said sublumens controls delivery of polymeric coating material to the tissue lumen.
 2. A catheter device as in claim 1, characterized in that the catheter includes at least one occluding balloon member disposed around the tubular body in alignment with the aperture of a sublumen, whereby fluid flow through the sublumen inflates the positioning balloon member.
 3. A catheter device according to claims 1-2, characterized in that the device includes two occluding balloons, one disposed toward the proximal end of the tubular body from the aperture of the sublumen which controls delivery of polymeric coating material, and the other disposed toward the distal end of the tubular body from the aperture of the sublumen which controls delivery of polymeric coating material, whereby the occluding balloons together act to at least partially occlude a portion of the tissue lumen.
 4. A catheter device as in claim 3, characterized in that the sublumen which controls polymer delivery forms a conduit between a vessel containing a monomer or prepolymer solution for the polymer coating and the tissue lumen.
 5. A catheter device as in claims 1-3, characterized in that an expansile member is disposed around the tubular body in alignment with the aperture of the sublumen that controls polymer delivery, whereby fluid flow through the sublumen that controls polymer delivery inflates the expansile member.
 6. A catheter device as in claim 5, characterized in that a partial or complete layer of polymeric coating material is disposed around the expansile member, whereby expansion of the balloon causes the polymeric material to expand to coat the tissue lumen.
 7. A catheter device as in claims 5-6, characterized in that a continuous, perforated or helical polymeric sleeve is disposed around the expansile member, whereby expansion of the balloon causes the polymeric material to expand to coat the tissue lumen.
 8. A catheter device as in claims 5-6, characterized in that the polymeric coating material is discontinuous and disposed on a mesh support.
 9. A catheter device as in claim 4, characterized in that there is an expansile member disposed around the tubular body in alignment with a further of said apertures and between the positioning balloons, whereby the thickness and surface configuration of the polymer coating is controlled by inflation of the expansile member.
 10. A catheter device as in claims 5-9, characterized in that the expansile member has a contoured surface whereby a molded shape is imparted to the polymeric coating.
 11. A catheter device as in claims 1-4 and 9-10, characterized in that the distal aperture of the sublumen controlling polymer deliver is shaped to provide flow acceleration.
 12. A catheter device as in claim 11, characterized in that the shaped aperture includes a flow propellant device.
 13. A catheter device as in claims 3-12, characterized in that inflation of the two occluding balloons is independently controllable.
 14. A catheter devices as in claims 1-13, characterized in that the device includes a heating element, whereby the polymeric coating material can be heated prior or subsequent to delivery to the tissue lumen.
 15. A catheter device as in claims 1-14, characterized in that the device includes an optical fiber whereby light can be delivered to the polymeric coating material.
 16. A catheter device as in claims 1-3, 5-8 and 13-15 characterized in that the device includes a mechanically retractable protective sheath.
 17. A catheter device as in claims 1-17, characterized in that the polymeric material includes one or more therapeutic agents.
 18. An at least partially preformed polymeric product for use in endoluminal paving and sealing.
 19. A polymeric product as in claim 18, characterized in that the polymer employed is partially polymerized.
 20. A polymeric product as in claim 19, characterized in that further polymerization of the polymeric product is thermally activated.
 21. A polymeric product as in claim 19, characterized in that further polymerization of the polymeric product is photoactivated.
 22. A polymeric product as in claims 18-21, characterized in that the polymer is biodegradable.
 23. A polymeric product as in claim 22, characterized in that the product comprises polygluconolactone or a polyanhydride.
 24. A polymeric product as in claims 18-21, characterized in that the product comprises polyethylene, polyvinyl chloride or ethylene vinyl acetate copolymer.
 25. A polymeric product as in claims 18-24, characterized in that the polymer is mechanically deformable at temperatures achievable in vivo.
 26. A polymeric product as in claims 18-25, characterized in that the product comprises one or more therapeutic or cell growth agents.
 27. A polymeric product as in claims 18-26, characterized in that the product is in the form of a continuous, perforated or helical sleeve.
 28. A polymeric product as in claim 27, characterized in that the thickness of the sleeve is from 0.005 mm to 5.0 mm.
 29. A polymeric product as in claims 27-28, characterized in that the sleeve is from 10 to 20 mm in length.
 30. A polymeric product as in claims 18-29, characterized in that the product is microporous.
 31. A polymeric product as in claims 18-29, characterized in that the product is macroporous.
 32. A polymeric product as in claims 18-31, characterized in that the polymeric material is disposed discontinuously on a mesh substrate.
 33. A polymeric product as in claims 18-32, characterized in that the polymeric material contains living cells to facilitate healing.
 34. A process for paving or sealing the interior surface of a tissue lumen comprising entering the interior of the tissue lumen and applying a layer of polymer material to the interior surface of the tissue lumen, wherein the polymer is in intimate and conforming contact with the tissue surface.
 35. A process as in claim 34, wherein the polymer is a biodegradable polymer.
 36. A process as in claims 34-35, wherein the polymer is applied in a preshaped form to the interior surface of the vessel or organ.
 37. A process as in claims 34-36, wherein the polymeric material contains a therapeutic agent.
 38. The process as in claims 34-37, wherein multiple polymers containing various therapeutic agents are applied.
 39. A process as in claims 34-38, characterized in that a catheter is used to position the polymeric material within the body.
 40. A process according to claims 34-40, characterized in that a catheter in accordance with claims 1-17 is used to position the polymeric material within the body.
 41. A process as in claims 34-41, characterized in that the polymeric material contains additives which promote organ regeneration. 